Should I wait in line to get this free mug? Should I walk to dinner rather than taking a taxi? Should I drive an extra fifteen minutes to go to the cheaper grocery store? Should I keep reading reviews for another twenty minutes to make sure I've really found the best hot water bottle that $10 can buy? These questions can be quite difficult to answer without a framework for valuing our time, especially since considerations of this sort tend to trigger cognitive biases. To figure out how much w...